To counter the immense technological advantage held by U.S. and allied forces during the Vietnam Conflict, the Viet Cong developed an extensive network of underground tunnel complexes. From these tunnels, which were concentrated mostly around Cu Chi but spread as far as the outskirts of Saigon, the enemy could effectively ambush American forces and then safely vanish underfoot. The tunnels became so highly developed that they eventually contained armories, hospitals, mess halls, manufacturing centers, and storage facilities. Some complexes ranged up to 40 miles long; the Cu Chi tunnel complex contained 130 miles of passageways.
